The meeting point for the local tour was changed at the last minute today. How do I keep a multilingual group from getting separated?

Today, for a half-day city tour, the meeting point had to be moved from the hotel entrance to a side street due to road closures. The group included guests speaking Chinese, English, and Spanish, and my biggest fear was that someone might only see one of the messages. I first had the tour guide send text, map screenshots, and photos of landmarks in the group chat, then had the hotel front desk…